CGAL users discussion list

["Eggersdorfer Maximilian" <>]

Thank you for your quick reply, Andreas!

I only used the 3d weighted alpha shapes before. There you could first create 
a triangulation and a weight for each point (weight = radius^2). With the 
triangulation I could create the alpha shapes. I am wondering if it is 
possible to do the same in 2d. I did not find this in the online manual for 
2d alhpa shapes and in the example all weigths are the same. I tried to use 
the 3d code with a data set in 2d but it did not work. 

Thanks again!
max



Max Eggersdorfer
Particle Technology Laboratory, ETH Zürich
Sonneggstrasse 3, ML F 18
CH-8092 Zurich (Switzerland)
+41 44 632 39 52


________________________________________
From: Andreas Fabri 
[]
Sent: Tuesday, January 04, 2011 8:59 PM
To: 

Subject: Re: [cgal-discuss] 2d weighted alpha shapes - various radii

hi maximilian,

the alpha has to do with the ball moving around.
if all radii are the same you obtain something
almost identical to just points.

andreas


On 04/01/2011 19:36, Eggersdorfer Maximilian wrote:
> Hello Everybody,
>
> I try to use the 2d weighted alpha shapes to calculate the projected 
> surface area of a union of balls. As far as I understand the alpha value is 
> the same for all points (all circles have the same radius). Has anybody 
> used 2d  weighted alpha shapes already with various radii for different 
> points?
>
> Thanks in advance!
> Best
> Max
>
>
> Max Eggersdorfer
> Particle Technology Laboratory, ETH Zürich
> Sonneggstrasse 3, ML F 18
> CH-8092 Zurich (Switzerland)
> +41 44 632 39 52
> <mailto:>
>


--
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project

phone: ++33.492.954.912    skype: andreas.fabri

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